Front suspension for a front drive vehicle

ABSTRACT

A front suspension for a front drive vehicle having lower and upper wishbones and a damping support device including a hydraulic jack and a coaxial coil spring. The lower part of the hydraulic jack is connected to the transverse support arm of the lower wishbone through a yoke whereby the hydraulic device straddles the transmission shaft of the vehicle. The pivot centers of the rear arm of the lower wishbone are on a line perpendicular to the wheel plane and the pivot centers of the steering link rod connecting the swivel axle unit of the wheel to the steering rack are on a line making an obtuse angle with the wheel plane.

Inventor AppL No.

Filed Patented Assignees Priority Armand Froumajou Pontoise, France Feb.25, 1969 Dec. 28, 1971 Automobiles Peugeot Paris,

Regie National dos Usines Renault Billancourt, France, part interest toeach May 15, 1968 France FRONT SUSPENSION FOR A FRONT DRIVE VEHICLE 4Claims, 4 Drawing Figs.

US. Cl 180/43, 280/962 Int. Cl 860k 17/30, Bg 3/20 Field of Search /43,42;

[56] References Cited UNITED STATES PATENTS 2,228,413 1/1941 Smalley /432,455,429 12/1948 Lucien 180/436 X 3,123,348 3/1964 Hildebrandt280/124.1 X 3,257,121 6/1966 Muller 280/962 FOREIGN PATENTS 712,0326/1965 Canada 180/43 Primary Examiner-A. Harry Levy Attorney-Burns,Doane, Swecker & Mathis ABSTRACT: A front suspension for a front drivevehicle having lower and upper wishbones and a damping support deviceincluding a hydraulic jack and a coaxial coil spring. The lower part ofthe hydraulic jack is connected to the transverse support arm of thelower wishbone through a yoke whereby the hydraulic device straddles thetransmission shaft of the vehicle. The pivot centers of the rear arm ofthe lower wishbone are on a line perpendicular to the wheel plane andthe pivot centers of the steering link rod connecting the swivel axleunit of the wheel to the steering rack are on a line making an obtuseangle with the wheel plane.

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1 W- 3 1 '%E E W l 1 v O 22 A 2 ll. 0? 3 3 2s 7' s .21 e a X FRONTSUSPENSION FOR A FRONT DRIVE VEHICLE The present invention relates to animproved suspension for a front drive and steering wheel of anautomobile vehicle, said suspension being of the type having upper andlower wishbones and a supporting and damping device consisting of ahydraulic shock absorber and a coaxial coil spring.

The invention provides a suspension wherein the lower part of thehydraulic shock absorber device is connected to the transverse supportarm of the lower wishbone through a yoke whereby it straddles thetransmission shaft.

Compared to the usual arrangements in which the damper is fixed eitherabove the transmission shaft or on the lower wishbone and is disposed toone side of this transmission shaft, the arrangement according to theinvention affords the following advantages:

the height of the suspension off the ground is reduced and thisfacilitates accommodating it in the vehicle;

it is possible to adopt an assembly geometry which achieves under thebest conditions the filtering of the rolling noises and directionalstability.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawing.

IN THE DRAWING FIG. I is an elevational view of a suspension accordingto the invention;

FIG. 2 is a plan view thereof partly in section;

FIG. 3 is a partial sectional view taken along line 33 of FIG. I, and

FIG. 4 is a sectional view similar to FIG. 2, on an enlarged scale, ofone of the pivotal mountings of the front arm of the lower wishbone.

According to the illustrated embodiment, the body of the vehicle isdesignated by the reference character A and the front wheel, which isboth a driving and steering wheel, by the reference character B. Thefront end of the vehicle is indicated by the arrow AV in FIG. 2.

This wheel is driven in rotation by a transmission shaft 1 which iscontained in a plane roughly vertical and perpendicular to the plane ofthe wheel and is journaled in a conventional manner in a swivel stubaxle unit 2.

A lower extension 3 of this stub axle unit is connected, through a balljoint 4 constituting a lower pivot point of the wheel, to an arm 5 whichis roughly transversal and constitutes the rear support element of alower wishbone whose front element consists of the arm 6.

The other end of the rear arm 5 is connected to the body through anelastically yieldable pivot 7 whose pivot axis is parallel to thelongitudinal axis of the vehicle.

The front arm 6 is secured to the body through a flexible pivot 8aligned with the pivot 7 of the rear arm and, moreover, to the rear arm5 through a flexible pivot 9 identical to the pivot 8. The pivot axis ofthis pivot 9 is also parallel to the longitudinal axis of the vehicle.

In respect of each of these pivots 8 and 9, the center journal orspindle l constituting the front end or rear end of the front arm 6 isjournaled (see FIGS. 2 and 4) in a metal bush 11 maintained in twoelastically yieldable sleeves 12 each provided with an outer shoulder.The distance between the outer flanks of the shoulders of the twosleeves I2 is less than the lengths of the bushes 11 which is defined ateach end by a flange or plate 13. This arrangement imparts to theassembly great flexibility for slight movements of rotation in plan ofthe arm about the pivot 7. These movements are limited by the abutmentof shoulders of the sleeves 12 against the flanges 13 so as to permitthe transmission of considerable forces which arise in the course ofrapid acceleration or braking.

An upper extension I4 of the stub axle unit 2 is connected, through aball joint 15 constituting an upper pivot point of the wheel, to anupper wishbone 16. The latter is connected to the body by two pivots l7and 18 having a common pivot axis which is parallel to the longitudinalaxis of the vehicle.

A damping and support device constituted in a conventional manner by ahydraulic shock absorber l9 and a concentric spring 20, connects thebody A to the lower rear arm 5, this device being pivoted to the arm 5through a yoke 22 whereby the device can straddle the transmission shaft1.

The wheel is steered through a link rod 23 pivoted at 24 to the rack 25and at 26 to the stub axle unit 2. This steering unit is located at therear of the axis of the wheel roughly in the horizontal plane of thelower wishbone.

As will be understood, the arrangement according to the inventionaffords the advantage of facilitating the accommodation of a damper ofsuitable length for a small height of the suspension off the ground, asin the case of a damper located to one side of the transmission shaft.Moreover, it ensures improved directional stability and a filtration ofthe rolling noises owing to the possibility, by virtue of the yoke 22,of placing the support arm 5 in a position perpendicular to thelongitudinal axis of the vehicle notwithstanding the presence of thetransmission shaft. This is impossible when this damper is located toone side of the transmission shaft.

Directional stability is achieved as a consequence of the configurationin plan of the quadrilateral abcd (FIG. 2) the comers of which consistof the centers of the pivots or ball joints 4 and 7 of the rear lowerarm 5 and 24 and 25 of the steering link rod 23, and in taking intoconsideration the microdeformations which occur for example uponapplication of a traction force (the same reasoning could apply in thecase of braking, the deformations being in this case in the oppositedirection).

The application of a traction force F at the center 0 (FIG. 2) of thewheel B results, on one hand, in a torque about the axis XX (FIG. 1)intersecting the centers of the lower pivot 4 and upper pivot 15 and, onthe other hand, in a slight forward displacement of the wheel B relativeto the body A.

The torque about the axis XX tends to steer the wheel inwardly andresults in a toe-in, whereas the movement of the wheel forwardly of thebody A tends to steer the wheel in the opposite opening direction owingto the quadrilateral shape abcd of which the side ab, embodied by thearm 5, is perpendicular to the plane of the wheel, whereas the side cd,embodied by the steering link rod 23, makes an obtuse angle with thisplane.

A perfect directional stability is therefore guaranteed by theopposition of these tendencies which cancel one another out.

The rolling vibrations and noises are filtered by the particulararrangement of the pivots 8 and 9 which have sufficient flexibility topermit the rear arm 5 to undergo slight movements of rotation in planabout the elastically yieldable pivot 7 so-as to absorb the shortlongitudinal displacements of the wheel relative to the body A.

Although a specific embodiment of the invention has been described, manymodification and changes may be made therein without departing from thescope of the invention as defined in the appended claims.

In particular, the front arm 6 of the lower wishbone could be part of atorsion bar interconnecting the two front wheels.

Having now described my invention what I claim as new and desire tosecure by Letters patent is:

l. A front suspension and steering structure for a front drive vehiclehaving a longitudinal axis and a body structure, said suspensioncomprising a wheel, a swivel axle unit carrying the wheel which iscontained in a plane parallel to said axis, an upper wishbone structurepivoted at one end to the axle unit and at another end to the bodystructure, a lower wishbone structure having a front arm and a rear arm,first pivotal connections respectively connecting a first portion of thefront arm to the body structure and a second portion of the front arm tothe rear arm, second pivotal connections respectively connecting a firstportion of the rear arm to the body structure and a second portion ofthe rear arm to the swivel axle unit, said second pivotal connectionshaving pivot centers located on a first line perpendicular to said planeof the wheel, the steering structure comprising a steering rack, asteering link rod, third pivotal connections respectively connecting afirst portion of the steering link rod to the steering rack and a secondportion of the steering link rod to the swivel axle unit, said thirdpivotal connections having pivot centers located on a second lineconvergent with said first line in a direction away from said axis, thepivot centers of said second and third pivotal connections constitutingcorners of an articulated quadrilateral structure, and a damping supportdevice comprising a hydraulic shock absorber and a coaxial coil springinterposed between the body structure and the lower wishbone structure,a lower part of the hydraulic shock absorber being combined with a yokepivotably connected to the rear arm, the yoke defining a space for thepassage of a transmission shaft driving the wheel.

2. A suspension as claimed in claim 1, wherein said first pivotalconnections are elastically yieldable and allow play in a directionparallel to said longitudinal axis.

3. A front suspension and steering structure for a front drive vehiclehaving a longitudinal axis and a body structure, said suspensioncomprising a wheel, a swivel axle unit carrying the wheel which iscontained in a plane parallel to said axis, an upper wishbone structurepivoted at one end to the axle unit and at another end to the bodystructure, a lower wishbone structure having a front arm and a rear arm,first pivotal connections respectively connecting a first portion of thefront arm to the body structure and a second portion of the front arm tothe rear arm, said first pivotal connections being elastically yieldableand allowing play in a direction parallel to said longitudinal axis,second pivotal connections respectively connecting a first portion ofthe rear arm to the body structure and a second portion of the rear armto the swivel axle unit, said second pivotal connections having pivotcenters located on a first line perpendicular to said plane of thewheel, the steering structure comprising a steering rack, a steeringlink rod, third pivotal connections respectively connecting a firstportion of the steering link rod to the steering rack and a secondportion of the steering link rod to the swivel axle unit, said thirdpivotal connections having pivot centers located on a second lineconvergent with said first line in a direction away from said axis, thepivot centers of said second and third pivotal connections constitutingcomers of an articulated quadrilateral structure.

4. A front suspension as claimed in claim 3, wherein each of said firstpivotal connections comprises a bush having flanges, a journal parallelto said axis and integral with the front arm and axially fixed in saidbush, and a sleeve structure having two shoulders, said flanges of thebush being in spaced relation to outer faces of the shoulders of thesleeve structure, said sleeve structures being respectively mounted onthe body structure and on the rear arm.

1. A front suspension and steering structure for a front drive vehiclehaving a longitudinal axis and a body structure, said suspensioncomprising a wheel, a swivel axle unit carrying the wheel which iscontained in a plane parallel to said axis, an upper wishbone structurepivoted at one end to the axle unit and at another end to the bodystructure, a lower wishbone structure having a front arm and a rear arm,first pivotal connections respectively connecting a first portion of thefront arm to the body structure and a second portion of the front arm tothe rear arm, second pivotal connections respectively connecting a firstportion of the rear arm to the body structure and a second portion ofthe rear arm to the swivel axle unit, said second pivotal connectionshaving pivot centers located on a first line perpendicular to said planeof the wheel, the steering structure comprising a steering rack, asteering link rod, third pivotal connections respectively connecting afirst portion of the steering link rod to the steering rack and a secondportion of the steering link rod to the swivel axle unit, said thirdpivotal connections having pivot centers located on a second lineconvergent with said first line in a direction away from said axis, thepivot centers of said second and third pivotal connections constitutingcorners of an articulated quadrilateral structure, and a damping supportdevice comprising a hydraulic shock absorber and a coaxial coil springinterposed between the body structure and the lower wishbone structure,a lower part of the hydraulic shock absorber being combined with a yokepivotably connected to the rear arm, the yoke defining a space for thepassage of a transmission shaft driving the wheel.
 2. A suspension asclaimed in claim 1, wherein said first pivotal connections areelastically yieldable and allow play in a direction parallel to saidlongitudinal axis.
 3. A front suspension and steering structure for afront drive vehicle having a longitudinal axis and a body structure,said suspension comprising a wheel, a swivel axle unit carrying thewheel which is contained in a plane parallel to said axis, an upperwishbone structure pivoted at one end to the axle unit and at anotherend to the body structure, a lower wishbone structure having a front armand a rear arm, first pivotal connections respectively connecting afirst portion of the front arm to the body structure and a secondportion of the front arm to the rear arm, said first pivotal connectionsbeing elastically yieldable and allowing play in a direction parallel tosaid longitudinal axis, second pivotal connections respectivelyconnecting a first portion of the rear arm to the body structure and asecond portion of the rear arm to the swivel axle unit, said secondpivotal connections having pivot centers located on a first lineperpendicular to said plane of the wheel, the steering structurecomprising a steering rack, a steering link rod, third pivotalconnections respectively connecting a first portion of the steering linkrod to the steering rack and a second portion of the steering link rodto the swivel axle unit, said third pivotal connections having pivotcenters located on a second line convergent with said first line in adirection away from said axis, the pivot centers of said second andthird pivotal connections constituting corners of an articulatedquadrilateral structure.
 4. A front suspension as clAimed in claim 3,wherein each of said first pivotal connections comprises a bush havingflanges, a journal parallel to said axis and integral with the front armand axially fixed in said bush, and a sleeve structure having twoshoulders, said flanges of the bush being in spaced relation to outerfaces of the shoulders of the sleeve structure, said sleeve structuresbeing respectively mounted on the body structure and on the rear arm.